We make Di2 battery holders for 25.4mm seat posts with various inside diameter size options. If you are using a seatpost not listed here, please contact us for assistance.
C2 - 19 mm ID (Carbon)
C3 - 19.5 mm ID (Aluminum)
SAVE - (unmodified)
BBB Basic - 19.65 mm ID (Aluminum)
SLK Carbon - 20.5 mm ID (Carbon)
Zipp Service Course SL Carbon - 22 mm mm ID (Carbon)
Ad hoc solutions using tape and foam have multiple issues. The net result is often a damaged or stuck battery.
Problems with Tape or Foam:
Removing the holder requires pliers. Never use pliers on the battery itself.
Out of Stock Items
Due to an overwhelming demand, some items are now sold out. We are working hard to produce the next batch of these items. At this time, we expect to be restocked by the week of October 10th.